This invention relates to a multi-space resonator conduit system for introducing intake gases into piston-type internal combustion engines. The conduit system is coupled to the intake openings of the engine cylinders.
The specific output or torque of piston-type internal combustion engines basically depends from the quantity of the intake gas drawn into the cylinders of the engine within one cycle. For this reason there are widely used methods and systems by means of which the quantity of the intake gas introduced into the cylinders can be increased. Such systems include various charging arrangements which, with the utilization of an external energy source or the energy derived from the exhaust gases increase the charging of the cylinders with intake gas. The known methods include processes such as the intake (suction) pipe charging which, for charging the cylinders, utilizes the non-steady flow generated by the periodic suction effect of the cylinders and the accompanying phenomena, that is, the pressure oscillations in the intake system.
The pressure oscillations caused by the non-steady intake gas flow may be particularly advantageously utilized in multi-space resonator conduit systems for the intake gas. In such systems at most four of those engine cylinders whose intake periods do not significantly overlap, are connected to the same resonator vessel. At least one resonance tube is coupled to each resonator vessel. The resonance tubes may obtain the intake gas directy from the surrounding atmosphere, but in case an air filter or, in particular, a charging arrangement is used, the resonance tubes are interconnected by a damping vessel which communicates with the air filter or the charging arrangement. Such a resonator conduit system for the intake gas is disclosed, for example, in Hungarian Patent No. 161,323 and German Patent No. 1,935,155.
In an intake gas conduit system of the above type, for example, in case of a four-cycle six-cylinder in-line engine--considering the usual ignition sequence of 1-5-3-6-2-4--the intake openings of a first cylinder group formed by the first, second and third cylinders are coupled to a first resonator vessel, while the intake openings of a second cylinder group formed by the fourth, fifth and sixth cylinders are coupled to a second resonator vessel. Thus, such an engine has two resonator vessels and at least two resonance tubes. The acoustic oscillating system formed of each resonator vessel and its resonance tube(s) has a natural frequency well defined by the linear dimensions of the system and by the velocity of sound in the intake gas. In case the intake frequency of the cylinders connected to the resonator vessel is identical to the natural frequency of the system, a resonance will appear in the acoustic oscillating system. The maximum charging effect is obtained in the range of that rpm where such a resonance condition is established. Such an rpm is referred to as the resonance rpm. It is apparent that by changing the natural frequency of the system, the resonance rpm may be adapted to a desired engine rpm. The charging effect--as it is disclosed, for example, in U.S. Pat. No. 3,796,048--may be advantageously increased in a wide rpm range by the appropriate selection of the dimensions of the system.
For a smooth running and a satisfactory operation of the engine, it is, however, indispensable that the intake gas supply to the cylinders of the individual cylinder groups be identical. In order to meet this requirement, the individual cylinder groups have a suction system that provides for identical charging effects. Thus, in case of resonance charging, they have resonator vessels and resonance tubes of identical dimensions and in case of suction pipe charging, the individual cylinders or cylinder groups have suction pipes of identical dimensions.
Difficulties have been encountered, however, in arranging the identically dimensioned suction pipes or, in case of resonator systems, the resonator vessels and resonance tubes in the space available at the engine. For overcoming these difficulties several solutions are known, such as disclosed, for example, in British Patent Nos. 866,660 and 1,015,417 as well as German Patent No. 1,048,083 for suction pipe chargers and, as disclosed in U.S. Pat. No. 4,064,696 for multi-space intake gas resonator systems.
Although the systems in the above-identified prior art and solutions similar thereto resolve positional problems in specific and particular cases, it is their common characteristic that the desired identity of the charging effect regarding the different cylinders is achieved by elements of identical dimensions. This means that these solutions have structural limitations in that they can be utilized only in certain predetermined engine arrangements and mounting conditions. In a large number of engine constructions or mounting modes, the known solutions cannot be resorted to, precisely because they call for fixed spatial requirements or arrangements.